Alternating-current oscillating motor



May 6 1924. 1,493,259 Y H. v. GREEN ALTERNATING CURRENT OSCILLATINGMOTOR Filed July 22 1922 Fig. I.

Inventor 2 H arold Green by Wflw is Attorney.

Patented May 6, 1924.

HAROLD V. cm, OF CHICAGO, ILLINOIS,

ASSIGNOB '10 GENERAL MC run, A CORPORATION 0! NEW YORK.

ALTEBNLTING-CUBBENT OBOILLATING ROTOR Application filed July 8%, I928.Serial Io. 578,711.

To all whom. it may corwem:

Be it known that I, HAROID V. GREEN, a

citizen of the United States, residing at 1 Chicago, in the county ofCook, State of 5 Illinois, have invented certain new and usefulImprovements in Alternating-Current Oscillating Motors, of which theollowing is a speci cation.

My invention relates to alternating ourrent motors of the reciprocatingtype and its principal ob'ect is to provide an improved motor 0 itsclass both as regards simplicity of construction and efiiciency. Afurther object is to eliminate the necessity of all switching devicesother than the line switch. Other advantages of my improved motor willappear as the description proceeds.

The features of my invention which I believe to be novel and patentablewill be pointed out in the claims appended hereto. The construction andtheory of operation of a motor built in accordance with my inventionwill now be described in connection with the accompanying drawings inwhich Fi 1 shows a section through the motor and Fig. 2 a top view ofthe same.

Referring now to the drawings and more in particular to Fig. 1, myimproved motor comprises an alternating current electromagnet adapted tobe excited with single phase current, an armature adapted to be vibratedin synchronism with said alternating current and a spring connected tothe armature adjusted to have the same f period of vibration as thearmature. In the illustration the magnetic circuit of the electro-magnetis in the form of a nearly closed E-shaped structure 1, preferablylaminated. The armature 2 is mounted in the open side of the E andarranged to reciprocate back and forth in ,the opening toward and awayfrom the middle leg 3 in response to flux impulses produced by singlephase current in the coil 4 wound about the middle leg 3. The armature 2is rigidly secured to a rod 5 preferabl of non-magnetic material, suchas brass, w ich in the present instance pasas through an REI'SSUEDopening 6 in the middle leg 3. The rod 5 1s secured in any suitablemanner to the rec end of a spring reed 7. The other end of the reed isclamped to the stationary portion of the motor, for example, by means ofthe frame 8, strap 9 and bolt 10.

he frame 8 preferably forms a casing integral with the base 11, betweenthe sides of which the laminations 1 are clamped by means of bolts 12.The ends and top of the casing thus formed are left open and 60 acentral opening indicated in dotted lines in Fig. 1 is provided in thetwo side pieces throu h which the coil 4 extends.

Wit the arrangement illustrated, the extent of vibration of the reed 7,rod 5 and 05 armature 2 is indicated by the dotted line positions ofreed 7 in Fig. 1. Where the amplitude of vibration is short and the read7 fairly long, the reed may be rigidly secured to rod 5, in which casethe rod 5 will be made slightly flexible and the clearance aroundarmature 2 and rod 5 sufiicient to permit the slight lateral movement ofthe free end of reed 7. This movement ma also be taken care of byproviding a sma l clearance between rod 5 and the opening in reed 7 andadjusting the lock nuts 14 with respect to collar 13 so that reed 7 mayslide relative thereto. Rod 5 might also be provided with a hinged joint'ust below collar 13 for this purpose. The length of reed 7 may be madeadjustable if desired in order to permit the use of the motor ondifi'erent requency sources. The armature 2 is secured to rod 5 in anyconvenient manner such as by collars 15 and pin 16.

When the winding 4 is excited from a source of single phase alternatincurrent, the armature 2 will tend to osci late back and forth insynchronism therewith and preferably with a period of vibrationequal invalue to the magnetic alternations; that is, twice the fre uency of thealternating current source. nles the spring 7 is selected to have aperiod of vibratlon equal to that of the armature, the amplitude will bevery small, due to the inertia of the moving parts. In order to producea useful vibration of the armature 2, spring 7 is selected to have anatural period of vibration' equal to or substantially equal to, thefrequency of the single phase source or some multiple thereof. In otherwords, I make use of the phenomena of mechanical resonance. The mostpractical arrangement for commercial frequencies will be where the riodof vibration of the spring is ua to twice the frequency of the singleglmse source. The resonant spring 7 serves to keep the armature invibration with a small amount of assistance from the electrical winding4, leaving the major part of will start to move upward again at the sametime the second flux impluse, which is now in the reverse direction,becomes effective. The armature will soon attain its full amplitude ofvibration and a certain amount of excess energy will be available fordoing work. The power factor of the. motor may be improved if desired byproviding a static condenser in parallel therewith.

In the illustration the base casting 11 also forms a'compression chamber18 provided with an inlet valve 19 and an outlet valve 20. The rod 5 isextended below. the armature 2 and attached to a piston 21 fitted in thecompression chamber 18. The rod 5 is attached to the piston 21 in anyconvenient manner. As thus illustrated, fluid is drawn in through valve19 on the upward stroke of the piston .and is expelled through valve 20on the downwardstroke. The section of the compression chamber 18occupied by the piston 21 is preferably cylindrical in shape althoughnot necessarily so.

The motor of the present invention is not intended to do heavy work butin applications requiring small amounts of power the motor will comparefavorably in efliciency and will be considerably less costly as comparedto the small rotary type electric motors. I do not wish to be limited tothe precise construction and use shown and described but seek to coverin the appended claims all modifications and usage coming fairly withinthe true scope of my invention. For instance, the spring 7 might beplaced on the same end of the motor as the armature and the opening 6 inthe middle leg 3 omitted. Likewise, in some cases, it may be preferableto use a spring rigidly secured atboth ends to the stationary part ofthe motor and have the middle of the spring constitute the vibratingportion and secured to the armature.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. An electric motor of the alternating reciprocating t e "comprisin anelectromagnet adapte to be excite with single phase alternatin current,an armature therefore adapt to be vibrated in synchronism with saidcurrent, a sprin reed having one portion rigidly support on a fixedabutment and another portion connected to said armature and adjusted tohave the same riod'of vibration as said armature. 2. electric motor ofthe reciprocating type comprising an electromagnet adapted to be excitedby an electric current of such a nature as to produce therein regularlrecurring flux pulsations, an armature t erefor responsive to said fluxpulsations and a spring having one portion in mechanical connection withsaid armature and another portion secured in fixed relation with respectto said electromagnet, the dimensions of said spring .being such as toproduce a condition of mechanical resonance between the armature andspring when said armature responds to said flux pulsations.

- 3. An electric motor of the reciprocating type comprising a frame, acore forming a artially closed magnetic circuit supported y said frame,an energizing coil for said core, a source of alternating current forexciting said coil an armature mounted to reciprocate in the opening insaid. core in response to flux pulsations produced therein by saidalternating current, a spring, having a natural period of vibratingsynchronone with the requency of said alternating current source,secured between said framework and armature and a machine 0 erated bysaid motor and integral therewit 4. An electric motor of thereciprocating type comprising a magnetic core, an energizing coilthereon, a source of alternating current for energizing said coil, anarmature for said electromagnet mounted in a position to be moved inresponse to flux pulsations in said core and a spring of the vibratintype secured between said armature an core adapted to be flexed whensaid armature responds to a flux pulsation, said spring having a naturalperiod of vibrat-ion synchronous with the frequency of said alternatingcurrent.

5. An electric motor of the reciprocating type comprising a three-legcore in the formof a substantially closed E, an energizing coil on themidle leg of said core, a source of electric energy for energizing saidcoil of Ill III

connected between said armature and core, sald sprlng havm a naturalperiod of v1- bration equal to the frequency of said flux pulsations.

In witness whereof, I have hereunto set my hand this 17th da of July,1922.

HA OLD V. GREEN.

